The Role of the Gut-Brain Axis on Neurodegenerative Diseases

Parkinson’s disease is the second most common neurodegenerative disease, following Alzheimer’s disease. It is characterized by a series of motor symptoms, however, there are multiple non-motor symptoms that also occur. At the microscopic level, there is a degeneration of dopaminergic receptors in the neurons, and also an accumulation of the misfolded protein alpha-synuclein, throughout the body. The majority of the depletion of these dopaminergic neurons occurs in the substantia nigra. Recently, research has pointed to a change in the environment of the gut microbiota as being responsible for the development of Parkinson’s disease. There is bidirectional communication between the gut and the brain; this is termed the gut—brain axis. When the gut microbiota environment is altered, the patient is susceptible to several issues, including inflammation. When the microbiome is altered, it has also been found that alpha-synuclein will aggregate. Parkinson’s is typically instigated by an external trigger, however, it has recently been found that a change in the gut microbiome may be enough of a trigger. Even if the cause of Parkinson’s disease is not found to reside within the discovery of the gut-brain axis, there is much potential for future treatments and therapies within it